A327985 Positions of zeros in A051023, the middle column of rule-30 1-D cellular automaton, when started from a lone 1 cell.

2, 6, 7, 10, 11, 12, 14, 17, 18, 20, 21, 25, 27, 31, 32, 36, 38, 40, 43, 44, 45, 46, 49, 50, 52, 54, 57, 59, 61, 68, 69, 70, 71, 76, 77, 78, 80, 82, 86, 87, 88, 89, 90, 92, 93, 95, 98, 99, 100, 104, 105, 106, 109, 112, 115, 117, 118, 119, 120, 121, 122, 123, 125, 126, 127, 133, 137, 139, 140, 144, 145, 146, 150, 152, 156

Offset: 1

Author

Antti Karttunen, Oct 03 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..100000
• Index entries for sequences related to cellular automata

Crossrefs

Cf. A051023, A226474 (characteristic function), A110240, A269160.

Cf. A327980 (first differences), A327984 (complement).

Programs

Mathematica

A327985list[upto_]:=Flatten[Position[CellularAutomaton[30,{{1},0},{upto,{{0}}}],0]]-1;A327985list[200] (* Paolo Xausa, Jun 28 2023 *)

PARI

A269160(n) = bitxor(n, bitor(2*n, 4*n)); \\ From A269160.
A110240(n) = if(!n,1,A269160(A110240(n-1)));
A051023(n) = ((A110240(n)>>n)%2);
isA327985(n) = !A051023(n);

PARI

A327985write(up_to) = { my(s=1, n=0, k=0); while(k>n)%2), k++; write("b327985.txt", k, " ", n)); s = A269160(s); n++); (n); }; \\ For fast creation of b-files.